Buy the book “Hooking Up” by PTPP, Pass the Pitons Pete, Pete Zabrok. It’s an absolute masterpiece with more useful aid climbing information than any normal person could possibly assimilate. There’s a whole section on solo climbing. Pete has climbed El Cap by 65 different routes and has spent 850 nights on the wall. Yes, 850. Hard to fathom (he likes to take his time).
I’ve been aid climbing for over 50 years and there are things in the book that blew my mind: soloing, hauling, how to jug traverses, lowering out bags, haulbag management, head placement, belay management, rapelling with bags etc. The list goes on.
Here’s his email: passthepitonspete@hotmail.com
He’s in Yosemite right now and has 300 copies of his book with him. He may not respond right away as he’s working on another El Cap project in his usual shit-show manner but I don’t think he’s heading up for good for 3 or 4 days so he may get back to you.
Tell him Don sent you his way
BTW-the book is 670 pages with lots of pictures and illustrations